A Balance Equation Determines a Switch in Neuronal Excitability
Figure 8
Variations of L-type calcium channel density induce excitability switches in a model of DA neurons
[3]. A. Bifurcation diagram of the model with as the bifurcation parameter. TC denotes a transcritical bifurcation, SN a saddle-node bifurcation. Branches of stable fixed points are represented as solid curves, branches of saddle points and unstable points as dashed curves. B. Electrophysiological responses of the model to step inputs of excitatory/inhibitory current (the intracellular calcium concentration is fixed at
, which is within the physiological range). For
lower (resp. higher) than the critical value
, the model exhibits typical electrophysiological signature of restorative (resp. regenerative) excitability. The low
configuration corresponds to
, whereas the high
configuration corresponds to
.